Stability Criterion for the Assembly of Core-Shell Lipid-Polymer-Nucleic Acid Nanoparticles

Hybrid core-shell lipid-polycation-nucleic acid nanoparticles (LPNPs) provide unique delivery strategies for nonviral gene therapeutics. Since LPNPs consist of multiple components, involving different pairwise interactions between them, they are challenging to characterize and understand. Here, we propose a method based on fluorescence cross-correlation spectroscopy to elucidate the association between the three LPNP components. Through this lens, we demonstrate that cationic lipid shells (liposomes) do not displace polycations or DNA from the polycation-DNA cores (polyplexes). Hence, polyplexes and liposomes must be oppositely charged to associate into LPNPs. Furthermore, we identify the liposome:polyplex number ratio (ρN), which was hitherto an intangible quantity, as the primary parameter predicting stable LPNPs. We establish that ρN ≥ 1 ensures that every polyplex is enveloped by a liposome, thus avoiding coexisting oppositely charged species prone to aggregation.

Advancing fluorescence microscopy and spectroscopy for the benefit of cell science and drug delivery

Here we report on two recent advances we made applying advanced fluorescence microscopy and spectroscopy to further the study of cell biology and drug delivery. At first, we detail a new instrumental set-up combining atomic force microscopy in liquid and super-resolution fluorescence microscopy in novel configuration such that long-term simultaneous and co-localized observation with both techniques becomes feasible. We believe this will contribute to the study of fast membrane activated cell-signalling processes in the years to come. Furthermore, we report on a novel application of fluorescence cross-correlation spectroscopy (FCCS) for the characterization of lipid-nucleic acid complexes. We could determine the number of nucleic acid particles incorporated in each liposome, a parameter not readily accessible on ensemble basis with other methods. This parameter is crucial for co-delivery applications, and we believe FCCS can play an important role in the future development of new drug delivery systems.

Medical imaging call centre: a communication success story

AIM

To evaluate utilisation of a medical imaging call centre (MICC) at a multi-site, academic radiology department, focusing on communication of critical, urgent, or significant unexpected findings.

MATERIALS AND METHODS

Institutional research ethics board approval was obtained. All calls made to MICC from 1 January to 31 December 2019 were reviewed retrospectively. The total number of calls, date, and reason of each call, level of report alert, and turnaround time (TAT) were recorded. Level 1, 2, and 3 alerts were defined as "potentially life-threatening new/unexpected findings", "could result in morbidity/mortality", or "not immediately life-threatening or urgent", respectively. TAT was defined as the time from alert request received by the MICC until acknowledgement of receipt by the referring physician, with a desired TAT of 60 min, 3 h, and 3 days for each level, respectively.

RESULTS

The MICC received 29,799 calls in 2019, on average 2,483 (range 1,989-3,098) calls per month. The most common indications for contacting the MICC were to request imaging reports to be expedited (14,916 calls, 50%) and issuing report alerts to communicate unexpected or urgent findings (7,060 calls, 24%). Average number and range of calls for Level 1, 2, and 3 alerts were 57 (39-80), 345 (307-388), and 187 (127-215) per month, respectively. Average TAT for Level 1, 2, and 3 report alerts were 59 min, 2 h 26 min, and 19 h 39 min, respectively.

CONCLUSION

The MICC received a large volume of calls and was a successful method for timely communication of unexpected or urgent imaging findings using a three-tiered alert system.

Spotting intruders: Species distribution models for managing invasive intertidal macroalgae

Invasive macroalgae represent one of the major threats to marine biodiversity, ecosystem functioning and structure, as well as being important drivers of ecosystem services depletion. Many such species have become well established along the west coast of the Iberian Peninsula. However, the lack of information about the distribution of the invaders and the factors determining their occurrence make bioinvasions a difficult issue to manage. Such information is key to enabling the design and implementation of effective management plans. The present study aimed to map the current probability of presence of six invasive macroalgae: Grateloupia turuturu, Asparagopsis armata, Colpomenia peregrina, Sargassum muticum, Undaria pinnatifida, and Codium fragile ssp. fragile. For this purpose, an extensive field survey was carried out along the coast of the north-western Iberian Peninsula. Species distribution models (SDMs) were then used to map the presence probability of these invasive species throughout the study region on the basis of environmental and anthropogenic predictor variables. The southern Galician rias were identified as the main hotspots of macroalgal invasion, with a high probability of occurrence for most of the species considered. Conversely, the probability of presence on the Portuguese coast was generally low. Physico-chemical variables were the most important factors for predicting the distribution of invasive macroalgae contributing between 57.27 and 85.24% to the ensemble models. However, anthropogenic factors (including size of vessels, number of shipping lines, distance from ports, population density, etc.) considerably improved the estimates of the probability of occurrence for most of the target species. This study is one of the few to include anthropogenic factors in SDMs for invasive macroalgae. The findings suggest that management actions aimed at controlling these species should strengthen control and surveillance at ports, particularly in southern Galician rias. Early detection should be of main concern for risk assessment plans on the Portuguese coast.

Transient Lipid-Protein Structures and Selective Ganglioside Uptake During α-Synuclein-Lipid Co-aggregation

α-Synuclein is a membrane-interacting protein involved in Parkinson's disease. Here we have investigated the co-association of α-synuclein and lipids from ganglioside-containing model membranes. Our study relies on the reported importance of ganglioside lipids, which are found in high amounts in neurons and exosomes, on cell-to-cell prion-like transmission of misfolded α-synuclein. Samples taken along various stages of the aggregation process were imaged using cryogenic transmission electron microscopy, and the composition of samples corresponding to the final state analyzed using NMR spectroscopy. The combined data shows that α-synuclein co-assembles with lipids from the ganglioside (GM1)-containing model membranes. The lipid-protein samples observed during the aggregation process contain non-vesicular objects not present at the final stage, thus capturing the co-existence of species under non-equilibrium conditions. A range of different lipid-protein co-assemblies are observed during the time course of the reaction and some of these appear to be transient assemblies that evolve into other co-aggregates over time. At the end of the aggregation reaction, the samples become more homogeneous, showing thin fibrillar structures heavily decorated with small vesicles. From the NMR analysis, we conclude that the ratio of GM1 to phosphatidyl choline (PC) in the supernatant of the co-aggregated samples is significantly reduced compared to the GM1/PC ratio of the lipid dispersion from which these samples were derived. Taken together, this indicates a selective uptake of GM1 into the fibrillar aggregates and removal of GM1-rich objects from the solution.

Fluorescence cross-correlation spectroscopy as a valuable tool to characterize cationic liposome-DNA nanoparticle assembly

The development of nonviral gene delivery vehicles for therapeutic applications requires methods capable of quantifying the association between the genes and their carrier counterparts. Here we investigate the potential of fluorescence cross-correlation spectroscopy (FCCS) to characterize and optimize the assembly of nonviral cationic liposome (CL)-DNA complexes based on a CL formulation consisting of the cationic lipid DOTAP and zwitterionic lipid DOPC. We use a DNA plasmid for lipoplex loading encoding the Oct4 gene, critically involved in reprogramming somatic cells into induced pluripotent stem cells. We demonstrate that FCCS is able to quantitatively determine the extent of the association between DNA and the liposomes and assess its loading capacity. We also establish that the cationic lipid fraction, being proportional to the liposome membrane charge density, as well as charge ratio between the CLs and anionic DNA play an important role in the degree of interaction between the liposomes and DNA.

Implementing Health Literacy Intelligence during COVI-19 outbreak

Background

During events that involve health risks, people may feel the need personal and social resources to cope with the demands posed by event. Depending on their individual characteristics, people may perceive their resources as sufficient or as insufficient to face the situation. Risk perception analysis was conducted in Portugal during the COVID-19 outbreak, to develop communication strategies, customized to the changing needs, helping people make informed decisions.

Methods

Citizens messages on social networks of 3 official information sources, and 8 media sources were analyzed between 26th January and 5th March 2020. A sample of comments to publications related to COVID-19 were analyzed in 4-days periods and categorized. A qualitative theory-driven thematic analysis was carried out based on two global categories: Demands and Resources. From this analysis, the threat level ratio (Demands/Resources) was calculated.

Results

A total of 8,251 comments were analysed in 10 periods of 4 days of data collection, from 26th January to 5th March. The threat level ratio increased during the first 15 days of analysis, having its maximum (6.80) in the period between the 7th and 14th of February, mostly associated with the perceived danger associated with the lack of airports arrivals control from China. After the announcement of the first confirmed case of COVID-19 in a Portuguese citizen outside Portugal, on 23rd February, the risk perception increased 1,4% compared to the previous period of analysis. On the contrary, after announcing the first confirmed case in Portugal, on the 1st March, the risk perception decreased 1,6%, which is inferred to be associated with a shift in the media discourse and to the use of humour.

Conclusions

Awareness of risks is a necessary condition for people to adhere to the necessary recommendations to mitigate the crisis. During an epidemic, an effective communication strategy can become an opportunity to promote health literacy.

Key messages

Risk perception is essential to define effective communication strategies to promote health literacy and best practices among targeted populations.

effective communication strategies customized to people’s needs and priorities help people making informed decisions during a public health emergency.

Influence of prenatal exposure to dexamethasone on neurodevelopmental behaviour

Introduction Early life stress, such as prenatal exposure to exogenous glucocorticoids (GC), can have a negative impact on brain development. Dexamethasone (DEX) is a synthetic GC used in preterm pregnancies to promote lung maturation. However, prenatal exposure to DEX induces an anxious-like behaviour in male and female offspring at adulthood. Notably, only males respond positively to therapeutics with a proposed anxiolytic.

Objectives Since the influence of prenatal DEX on neurodevelopmental behaviour remains to be elucidated and could help explain this difference in drug efficacy, we aim to clarify the effects of this GC on neurodevelopment during infancy, comparing male and female offspring neurodevelopment at this early age.

Methodology To obtain an animal model of chronic anxiety, Wistar pregnant dams were injected subcutaneously with DEX (1mg/kg) on gestational days 18 and 19. The vestibular system development, locomotion, upper limbs strength, discriminatory ability, auditory response and eye opening day were assessed in male and female offspring between P5 and P17. Animal procedures were approved by the Animal Welfare Committee and done in agreement with the law.

Results Male and female offspring prenatally exposed to DEX had a better performance in the tests assessing the vestibular system development and discriminatory ability, especially at P5 and P6. Additionally, DEX anticipated the day of eye opening and had a positive impact in the upper limb strength of the offspring of both sexes. However, the locomotor ability and auditory response were impaired comparing with controls.

Conclusion Exposure to DEX improves limb strength, balance, spatial orientation and anticipates eye opening. These results may suggest that prenatal DEX exposure promotes offspring development and maturation in both males and females. Prenatal DEX did not differently affect male and female neurodevelopment at early age. It remains to clarify the underlying motives that induce a dimorphic gender response to anxiolytic therapy in adulthood.

Pollen Proteases Play Multiple Roles in Allergic Disorders

Allergic diseases are a major health concern worldwide. Pollens are important triggers for allergic rhinitis, conjunctivitis and asthma. Proteases released upon pollen grain hydration appear to play a major role in the typical immunological and inflammatory responses that occur in patients with allergic disorders. In this study, we aimed to identify specific proteolytic activity in a set of pollens with diverse allergenic potential. Diffusates from Chenopodium album, Plantago lanceolata and Eucalyptus globulus were added to a confluent monolayer of Calu-3 cells grown in an air-liquid interface system. We identified serine proteases and metalloproteinases in all pollen diffusates investigated. Proteases found in these pollen diffusates were shown to compromise the integrity of the lung epithelial barrier by disrupting transmembrane adhesion proteins E-cadherin, claudin-1 and Occludin, as well as, the cytosolic complex zonula occludens-1 (ZO-1) resulting in a time-dependent increase in transepithelial permeability. Tight junction disruption and increased transepithelial permeability facilitates allergen exposure to epithelial sub-layers contributing to the sensitization to a wide range of allergens. These pollen extracts also induced an increase in the release of interleukin 6 (IL-6) and interleukin 8 (IL-8) cytokines measured by flow cytometry possibly as a result of the activation of protease-activated receptors 2 (PAR-2).

Ganglioside lipids accelerate α-synuclein amyloid formation

The deposition of α-synuclein fibrils is one hallmark of Parkinson's disease. Here, we investigate how ganglioside lipids, present in high amounts in neurons and exosomes, influence the aggregation kinetics of α-synuclein. Gangliosides, as well as, other anionic lipid species with small or large headgroups were found to induce conformational changes of α-synuclein monomers and catalyse their aggregation at mildly acidic conditions. Although the extent of this catalytic effect was slightly higher for gangliosides, the results imply that charge interactions are more important than headgroup chemistry in triggering aggregation. In support of this idea, uncharged lipids with large headgroups were not found to induce any conformational change and only weakly catalyse aggregation. Intriguingly, aggregation was also triggered by free ganglioside headgroups, while these caused no conformational change of α-synuclein monomers. Our data reveal that partially folded α-synuclein helical intermediates are not required species in triggering of α-synuclein aggregation.

Liver transplant recipients have a higher prevalence of anal squamous intraepithelial lesions

Background:

Anal squamous intraepithelial lesions (ASIL) are precancerous lesions of anal squamous cell carcinoma, with a higher prevalence in immunosuppressed patients. There are some studies in kidney transplant recipients, but there is no information regarding prevalence in liver transplantation. Our aim was to evaluate the prevalence of ASIL in this setting.

Methods:

Prospective case–control study involving liver transplant recipients without any other known risk factor for ASIL (n=59), which were compared with a healthy control group (n=57). All were submitted to anal cytology and high-resolution anoscopy was performed in those with abnormal results.

Results:

Ten (17%) of liver transplant recipients had abnormal cytological results, seven patients had atypical squamous cells of undetermined significance (ASC-US), one patient had atypical squamous cells that cannot exclude high-grade (ASC-H) and two patients had high-grade squamous intraepithelial lesions (HSIL). In the control group, one patient (2%) had an ASC-US result (P=0.005). Anal squamous intraepithelial lesions were confirmed in 7 out of 10 of liver transplant patients and 0 out of 1 in the controls (P=0.013) by high-resolution anoscopy with biopsies. Current smoking was the only risk factor for abnormal cytology (odds ratio=5.87, 95% confidence intervals=1.22–28.12, P=0.027).

Conclusions:

Liver transplant patients have a higher risk of ASIL. Screening should be considered, especially in smokers.

Corneal properties and glaucoma: a review of the literature and meta-analysis

PURPOSE

Studies have suggested that corneal biomechanical properties influence intraocular pressure (IOP) measurements, namely central corneal thickness (CCT) and corneal hysteresis (CH). The present study aimed to investigate the associations of CH and CCT with glaucoma development.

METHODS

We performed a review of the literature and meta-analysis of observational studies (2006-2016) that included both adult glaucoma patients and controls and reported CCT and CH as outcomes. Nineteen studies were conside red eligible, and the mean difference (MD) between groups (patient and control) for both variables was used for statistical analyses.

RESULTS

A total of 1,213 glaucoma and 1,055 healthy eyes were studied. Quan titative analysis suggested that CH was significantly lower in the glaucoma group than in the control group (MD=-1.54 mmHg, 95% CI [-1.68, -1.41], P<0.0001). Additionally, CCT was significantly lower in the glaucoma group than in the control group (MD=-8.49 µm, 95% CI [-11.36, -5.62], P<0.001).

CONCLUSION

Corneal properties appear to differ between glaucoma patients and healthy controls. Our results emphasize the importance of corneal biomechanical properties in IOP interpretation and should support further studies on the influence of CH and CCT in glaucoma screening and diagnosis.

Alteration in expressions of RhoA and Rho-kinases during pregnancy in rats: their roles in uterine contractions and onset of labour

Activation of RhoA and Rho-associated kinases (ROCKs) is known to play a pivotal role in the regulation of smooth muscle contraction via phosphorylation of myosin-light chain and myosin phosphatase. There are few data on the RhoA and ROCKs expression levels in rat uteri. Therefore, our aim was to investigate the mRNA and protein concentration of RhoA and ROCKs in rat uterus during pregnancy, during parturition and post-partum using real time PCR and Western blot analysis. The other purpose was to evaluate the effects of the ROCK (Y-27632, fasudil and RKI 1441) and RhoA inhibitors (simvastatin) on uterine contractility in isolated organ bath experiments. The mRNA and protein levels of RhoA decreased on the 5th day of pregnancy to day 22, then a sharp increase was detected at term. The mRNA and protein concentration of ROCKs was down-regulated in the early stage of pregnancy, while it sharply increased during parturition. The RhoA-inhibitor simvastatin relaxed the uterus contractions, although its inhibitory effects were not followed by the alteration of RhoA. The strongest inhibitory effect of non-selective ROCK inhibitor fasudil was found on non-pregnant uterus, while it elicited milder relaxation on day 22, during parturition and postpartum day 1. The maximum relaxing effects of Y-27632 and RKI 1441 were altered in a proportional way with the target protein expressions. The RhoA/ROCK signalling pathway might be a potential target for the development of new tocolytic agents; however, high specificity to RhoA, ROCK I or ROCK II seems to be fundamental to the high efficacy of uterine relaxation.

Acceleration of α-synuclein aggregation by exosomes

Exosomes are small vesicles released from cells into extracellular space. We have isolated exosomes from neuroblastoma cells and investigated their influence on the aggregation of α-synuclein, a protein associated with Parkinson disease pathology. Using cryo-transmission electron microscopy of exosomes, we found spherical unilamellar vesicles with a significant protein content, and Western blot analysis revealed that they contain, as expected, the proteins Flotillin-1 and Alix. Using thioflavin T fluorescence to monitor aggregation kinetics, we found that exosomes catalyze the process in a similar manner as a low concentration of preformed α-synuclein fibrils. The exosomes reduce the lag time indicating that they provide catalytic environments for nucleation. The catalytic effects of exosomes derived from naive cells and cells that overexpress α-synuclein do not differ. Vesicles prepared from extracted exosome lipids accelerate aggregation, suggesting that the lipids in exosomes are sufficient for the catalytic effect to arise. Using mass spectrometry, we found several phospholipid classes in the exosomes, including phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, phosphatidylinositol, and the gangliosides GM2 and GM3. Within each class, several species with different acyl chains were identified. We then prepared vesicles from corresponding pure lipids or defined mixtures, most of which were found to retard α-synuclein aggregation. As a striking exception, vesicles containing ganglioside lipids GM1 or GM3 accelerate the process. Understanding how α-synuclein interacts with biological membranes to promote neurological disease might lead to the identification of novel therapeutic targets.

Preclinical development of siRNA therapeutics: towards the match between fundamental science and engineered systems

The evolution of synthetic RNAi faces the paradox of interfering with the human biological environment. Due to the fact that all cell physiological processes can be target candidates, silencing a precise biological pathway could be challenging if target selectivity is not properly addressed. Molecular biology has provided scientific tools to suppress some of the most critical issues in gene therapy, while setting the standards for siRNA clinical application. However, the protein down-regulation through the mRNA silencing is intimately related to the sequence-specific siRNA ability to interact accurately with the potential target. Moreover, its in vivo biological fate is highly dependent on the successful design of a vehicle able to overcome both extracellular and intracellular barriers. Anticipating a great deal of innovation, crucial to meet the challenges involved in the RNAi therapeutics, the present review intends to build up a synopsis on the delivery strategies currently developed.

FROM THE CLINICAL EDITOR

This review discusses recent progress and pertinent limiting factors related to the use of siRNA-s as efficient protein-specific "silencing" agents, focusing on targeted delivery not only to cells of interest, but to the proper intracellular destination.

Ontogeny of sulfonylurea-binding regulatory subunits of K(ATP) channels in the pregnant rat myometrium

ATP-sensitive potassium channels (K(ATP) channels) are composed of sulfonylurea receptors (SURs) and potassium inward rectifiers (Kir(6.x)) that assemble to form a large octameric channel. This study was designed to examine the expression and role of sulfonylurea-binding regulatory subunits 1 (SUR1 (ABCC8)) and 2 (SUR2 (ABCC9)) of the K(ATP) channels in the pregnant rat myometrium with particular regard to the contractility. RT-PCR and western blot analyses were performed to detect the presence of SUR1 and SUR2. The SUR1 levels were markedly increased in the early stages of pregnancy. The highest level was detected on day 6 of pregnancy, whereas in the late stages, the levels of SUR1 were significantly decreased. The SUR2 level remained unchanged throughout pregnancy. The SUR non-selective diazoxide and the SUR2-selective pinacidil inhibited oxytocin-induced contractions. Glibenclamide, a K(ATP) channel blocker, antagonized both pinacidil- and diazoxide-induced relaxations. It was established that SURs are responsible for pharmacological reactivity of K(ATP) channel openers. We conclude that both SURs are involved in the K(ATP) channel in the pregnant rat myometrium. It may further be concluded that 'pinacidil-like' K(ATP) channel openers may be of therapeutic relevance as tocolytic agents in the future.

The Third Injection Technique Workshop in Athens (TITAN)

The first Injection Technique workshop brought together endocrinologists and injection experts from around the world in Strasbourg in 1997. From its work came groundbreaking recommendations which advanced best practices in areas such as the use of a skin fold when injecting. The second Injection Technique workshop, with an expanded format including nurses and diabetes educators, took place in Barcelona in 2000. The initial stimulus to use shorter injecting needles can be said to date from this meeting. The third Injection Technique workshop was held in Athens in September 2009 and involved 127 experts from across the globe. After a comprehensive review of all publications since 2000 as well as several unpublished studies, the attendees divided into smaller groups to debate and draft new injecting recommendations based on the new data and their collective experience. This paper summarizes all the formal presentations given at this practical consensus workshop.

New injection recommendations for patients with diabetes

AIM

Injections administered by patients are one of the mainstays of diabetes management. Proper injection technique is vital to avoiding intramuscular injections, ensuring appropriate delivery to the subcutaneous tissues and avoiding common complications such as lipohypertrophy. Yet few formal guidelines have been published summarizing all that is known about best practice. We propose new injection guidelines which are thoroughly evidence-based, written and vetted by a large group of international injection experts.

METHODS

A systematic literature study was conducted for all peer-reviewed studies and publications which bear on injections in diabetes. An international group of experts met regularly over a two-year period to review this literature and draft the recommendations. These were then presented for review and revision to 127 experts from 27 countries at the TITAN workshop in September, 2009.

RESULTS

Of 292 articles reviewed, 157 were found to meet the criteria of relevance to the recommendations. Each recommendation was graded by the weight it should have in daily practice and by its degree of support in the medical literature. The topics covered include The Role of the Professional, Psychological Challenges, Education, Site Care, Storage, Suspension and Priming, Injecting Process, Proper Use of Pens and Syringes, Insulin analogues, Human and Pre-mixed Insulins, GLP-1 analogs, Needle Length, Skin Folds, Lipohypertrophy, Rotation, Bleeding and Bruising, Pregnancy, Safety and Disposal.

CONCLUSION

These injecting recommendations provide practical guidance and fill an important gap in diabetes management. If followed, they should help ensure comfortable, effective and largely complication-free injections.

Penicillium glabrum cork-colonising isolates - preliminary analysis of their genomic similarity

The cork stopper manufacturing process includes an operation, known as stabilisation, by which humid cork slabs are extensively colonised by fungi. The effects of fungal growth on cork are not completely understood although they are considered to be involved in the so-called "cork taint" of wine. It is essential to (a) identify environmental constraints which define the appearance of the colonising fungal species and (b) trace their origin to the forest and/or the manufacturing space. The present article correlates two sets of data, from consecutive years and the same season, of systematic sampling of two manufacturing units, located in the North and South of Portugal. Chrysonilia sitophila dominance was confirmed, followed by a high diversity of Penicillium species. Penicillium glabrum, which was found in all samples, was the most frequently isolated species. P. glabrum intra-species variability was investigated using DNA fingerprinting techniques revealing highly discriminative polymorphic markers in the genome. Cluster analysis of P. glabrum data was discussed in relation to the geographical location of strains, and results suggest that P. glabrum arise from predominantly the manufacturing space, although cork specific fungi can contribute.

Antagonist G-mediated targeting and cytotoxicity of liposomal doxorubicin in NCI-H82 variant small cell lung cancer

The aim of the present study was to characterize the interactions of antagonist G (H-Arg-D-Trp-N(me)Phe-D-Trp-Leu-Met-NH 2)-targeted sterically stabilized liposomes with the human variant small cell lung cancer (SCLC) H82 cell line and to evaluate the antiproliferative activity of encapsulated doxorubicin against this cell line. Variant SCLC tumors are known to be more resistant to chemotherapy than classic SCLC tumors. The cellular association of antagonist G-targeted (radiolabeled) liposomes was 20-30-fold higher than that of non-targeted liposomes. Our data suggest that a maximum of 12,000 antagonist G-targeted liposomes were internalized/cell during 1-h incubation at 37 masculine C. Confocal microscopy experiments using pyranine-containing liposomes further confirmed that receptor-mediated endocytosis occurred, specifically in the case of targeted liposomes. In any of the previously mentioned experiments, the binding and endocytosis of non-targeted liposomes have revealed to be negligible. The improved cellular association of antagonist G-targeted liposomes, relative to non-targeted liposomes, resulted in an enhanced nuclear delivery (evaluated by fluorimetry) and cytotoxicity of encapsulated doxorubicin for incubation periods as short as 2 h. For an incubation of 2 h, we report IC50 values for targeted and non-targeted liposomes containing doxorubicin of 5.7 +/- 3.7 and higher than 200 micro M doxorubicin, respectively. Based on the present data, we may infer that receptors for antagonist G were present in H82 tumor cells and could mediate the internalization of antagonist G-targeted liposomes and the intracellular delivery of their content. Antagonist G covalently coupled to liposomal drugs may be promising for the treatment of this aggressive and highly heterogeneous disease.

Incidence and type of cervical spine injuries associated with mandibular fractures

The incidence of facial fractures accompanied by spinal injuries, while low, is of significant concern to the craniomaxillofacial surgeon. There are conflicting reports on the association between facial fractures and concomitant spinal damage. This retrospective study of 424 patients with mandibular fractures examines the relationship of mandibular fractures and concomitant spinal injuries. The incidence of concurrent mandibular and cervical fractures was 2.6%, predominantly associated with motor vehicle accidents. The purpose of this study is to examine the incidence of cervical spine injury associated with mandibular fractures, in order to improve the diagnosis and treatment of spinal injury associated with mandibular fractures.

Targeting Stealth liposomes in a murine model of human small cell lung cancer

Tumor accumulation and therapeutic activity of Stealth liposomes loaded with doxorubicin (DXR) were examined in Balb/c nude mice xenografts inoculated subcutaneously with the human small cell lung cancer (SCLC) cell line, H69. Mice were treated with non-targeted liposomes (SL) or liposomes targeted with antagonist G coupled to the liposome surface (SLG). SLG showed 30-44-fold higher binding to H69 cells harvested from H69 xenografts than SL. At 48 and 72 h post injection, tumor accumulation of [(125)I]tyraminylinulin-containing liposomes was shown to be dependent on liposome size but independent of the presence of the targeting ligand. Maximum tumor uptake of either SLG or SL ranged from 2 to 4% of injected dose/g of tissue. In therapeutic studies, mice received three weekly injections of 3 or 6 mg free DXR/kg or 3 or 10 mg liposomal DXR/kg at initial tumor volumes of either 7 or 33 mm(3). The therapeutic efficacy of DXR-containing SL or SLG was significantly improved over free DXR, but SLG did not improve anti-tumor efficacy relative to SL. Stealth liposomes containing DXR have potential as a therapy against human SCLC tumors.

A growth factor antagonist as a targeting agent for sterically stabilized liposomes in human small cell lung cancer

The ability of a growth factor antagonist, [D-Arg(6),D-Trp(7,9)-N(me)Phe(8)]-substance P(6-11), named antagonist G, to selectively target polyethylene glycol-grafted liposomes (known as sterically stabilized liposomes) to a human classical small cell lung cancer (SCLC) cell line, H69, was examined. Our results showed that radiolabeled antagonist G-targeted sterically stabilized liposomes (SLG) bound to H69 cells with higher avidity than free antagonist G and were internalized (reaching a maximum of 13000 SLG/cell), mainly through a receptor-mediated process, likely involving clathrin-coated pits. This interaction was confirmed by confocal microscopy to be peptide- and cell-specific. Moreover, it was shown that SLG significantly improved the nuclear delivery of encapsulated doxorubicin to the target cells, increasing the cytotoxic activity of the drug over non-targeted liposomes. In mice, [(125)I]tyraminylinulin-containing SLG were long circulating, with a half-life of 13 h. Use of peptides like antagonist G to promote binding and internalization of sterically stabilized liposomes, with their accompanying drug loads, i.e., anticancer drugs, genes or antisense oligonucleotides, into target cells has the potential to improve therapy of SCLC.

The Ross procedure: Is it the ideal operation for the young with aortic valve disease?

BACKGROUND

Aortic valve prosthesis with adequate hemodynamic performance should allow more complete left ventricular mass regression and normalize left ventricular function. This possibly affects long-term prognosis after aortic valve replacement.

OBJECTIVE

Assessment of hemodynamic performance of pulmonary autograft in the aortic position and the regression of left ventricular mass after the Ross procedure.

METHODS

Between May 1995 and March 1996, 45 patients with mean age of 27.1 years underwent a Ross procedure. Doppler echocardiography and cardiac catheterization were performed on all patients before hospital discharge to evaluate the hemodynamic performance of auto- and homografts, as well as to evaluate left ventricular mass and function. Fourteen patients with follow-up longer than six months were submitted to dobutamine stress echocardiography to study the hemodynamic performance of auto- and homografts during exercise.

RESULTS

Hospital mortality was 6%. After a mean follow-up of 12.8 months (1-23 months) there was one late sudden death. No valve-related event was observed during this period. Immediate and late hemodynamic performance of the pulmonary autografts were normal with an average mean gradient of 1.8 +/- 0.6 mmHg and an average maximum instantaneous gradient of 2.9 +/- 0.9 mmHg. Valvular insufficiency was insignificant. Even during exercise, gradients did not increase significantly with an average mean gradient of 4.3 +/- 2.5 mmHg and an average maximum gradient of 10.4 +/- 6.1 mmHg. Homografts used for right ventricular reconstruction showed excellent immediate hemodynamic performance. However, at late follow-up an increase in flow speed was observed with an average to mean gradient of 10 +/- 7.1 mmHg at rest and 26 +/- 13.2 mmHg during exercise. Left ventricular mass index was normal at rest and during exercise in the majority of patients.

CONCLUSION

Given the normal hemodynamic function of pulmonary autografts, the reduction of ventricular mass and normalization of left ventricular function, in addition to the excellent late follow-up of the patients, the Ross procedure is considered the operation of choice for young patients requiring aortic valve replacement.

Enhancement of toluidine blue staining by transforming growth factor-beta, insulin-like growth factor and growth hormone in the temporomandibular joint of aged mice

Osteoarthritic lesions appear in the articular cartilage of the temporomandibular joint of mice aged 7 months and older. Reduced rate of proteoglycan (PG) synthesis leading to destruction of the articular cartilage was observed in this joint. The purpose of the present study was to test the ability of transforming growth factor-beta1 (TGF-beta1), insulin-like growth factor-1 (IGF-1) and growth hormone (GH) to induce PG synthesis in joint cartilage of aged animals and to compare it with the effect of interleukin-1alpha (IL-1alpha). Mandibular condyle explants from 18-month-old mice were cultured up to 72 h in serum-free medium, supplemented with IL-1alpha (TGF-beta1 (0.1-5.0 ng/ml), TGF-beta1 (1.0 ng/ml) + IGF-1 (2 ng/ml) or GH (10 ng/ml). The incorporation of (35)S-SO(4) into sulfated PG was tested. Cartilage samples were processed for histomorphometry using sections stained with 0.1% toluidine blue (TB), pH 1.8. Results indicated that in cultures supplemented (48 h) with either TGF-beta, TGF-beta + IGF-1 or with GH, an increased height and area of TB-positive staining as well as increased incorporation of (35)S-SO(4) into sulfated PG were observed. In contrast, the cytokine IL-1alpha exerted an inhibitory effect on TB staining and on (35)S-SO(4) incorporation. The present study demonstrated that in vitro supplementation of IL-1alpha to mandibular condyle cartilage reduced the height and area of TB staining and incorporation of (35)S-SO(4), whereas TGF-beta1, TGF-beta1 + IGF-1 or GH increased the height and area of TB staining and increased incorporation of (35)S-SO(4). The two parameters used to identify increased PG synthesis were shown to reveal similar results and were useful for studying the dynamic events taking place in cartilage destruction and repair in osteoarthritis.

Does low-dose aspirin therapy complicate oral surgical procedures?

BACKGROUND

The fear of uncontrolled bleeding often prompts medical practitioners to stop aspirin intake for seven to 10 days before any surgical procedure. The authors initiated this study to evaluate the effect of aspirin on bleeding in patients undergoing oral surgery.

METHODS

The study group consisted of 39 patients who were scheduled to undergo dental extractions. All patients were receiving 100 milligrams of aspirin daily on a regular basis. The authors randomly divided the patients into two groups: those who stopped the aspirin therapy before the procedure and those who continued the aspirin therapy. One hour before the procedures, all patients underwent a bleeding time test. In addition, the amount of bleeding during the procedure was measured.

RESULTS

The mean (+/- standard deviation) bleeding time was 1.8 +/- 0.47 minutes for patients who stopped aspirin therapy one week before the procedure. For patients who continued aspirin therapy, the bleeding time was 3.1 +/- 0.65 minutes. The difference was statistically significant (P = .004). However, both groups were within the normal bleeding time range, and in both groups, a local hemostatic method was sufficient to control bleeding. No episodes of uncontrolled intraoperative or postoperative bleeding were noted.

CONCLUSION

Low-dose aspirin therapy should not be stopped before oral surgery. Local hemostasis is sufficient to control bleeding.

CLINICAL IMPLICATIONS

Patients receiving aspirin therapy to prevent blood clot formation may be subject to emboli formation if the treatment is stopped. The results of this study show that aspirin therapy should be continued throughout oral surgical procedures. Local measures are sufficient to control any bleeding during surgery.

Human serum albumin enhances DNA transfection by lipoplexes and confers resistance to inhibition by serum

Cationic liposome-DNA complexes ('lipoplexes') are used as gene delivery vehicles and may overcome some of the limitations of viral vectors for gene therapy applications. The interaction of highly positively charged lipoplexes with biological macromolecules in blood and tissues is one of the drawbacks of this system. We examined whether coating cationic liposomes with human serum albumin (HSA) could generate complexes that maintained transfection activity. The association of HSA with liposomes composed of 1, 2-dioleoyl-3-(trimethylammonium) propane and dioleoylphosphatidylethanolamine, and subsequent complexation with the plasmid pCMVluc greatly increased luciferase expression in epithelial and lymphocytic cell lines above that obtained with plain lipoplexes. The percentage of cells transfected also increased by an order of magnitude. The zeta potential of the ternary complexes was lower than that of the lipoplexes. Transfection activity by HSA-lipoplexes was not inhibited by up to 30% serum. The combined use of HSA and a pH-sensitive peptide resulted in significant gene expression in human primary macrophages. HSA-lipoplexes mediated significantly higher gene expression than plain lipoplexes or naked DNA in the lungs and spleen of mice. Our results indicate that negatively charged HSA-lipoplexes can facilitate efficient transfection of cultured cells, and that they may overcome some of the problems associated with the use of highly positively charged complexes for gene delivery in vivo.